I have an HP Server and two Storage Arrays. HP Server has two ports for the mini SAS External Cable and one of it is currently connected to the port on the 1st Storage Array labeled 'IN'. I want to add a second storage array. How should I connect the second one? Since I have one extra port from the Server do I directly connect the second storage array there or shall I cascade the 1st and the 2nd storage array ('OUT' of the first to 'IN' of the 2nd).

Using simple logic, I think it's usually best to dedicate a port (or SCSI channel) to one device.

Generally you get better performance, the computer can better distribute IN and OUT traffic, one array will not be as affected by the other's activity, logging is more organized and the system will be easier to troubleshoot.

FWIW I am not an external storage expert but these are the general rules I go by when setting up a system.

This is, of course, unless you have another use for the second port or the application has a problem dealing with the separate ports..

Think the old world - putting your CD-Writer as a slave to your main IDE drive caused countless errors in burning due to sharing of insufficient resources. So .... we put the Writer on the secondary IDE channel as a master and 'POOF' - problems eradicated.